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OF  ILLINOIS 

LIBRARY 


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Digitized  by  the  Internet  Archive 

in  2011  with  funding  from 

University  of  Illinois  Urbana-Champaign 


http://www.archive.org/details/effectofpractice27glic 


Reavis,  W.  C.    "The  importance  of  studv  programs  for  high-school  pupils,"  School 

Review,   19:398-405,  June,   1911. 
Robert,   A.  C.    '"Supervised   studv   in   the   E\erett   High   School,"   School   Review. 

24:73545.  December.  1916. 
Ryxe.arsox,    Edward.     "The    conference    hour    in    the    Pittsburgh    high    schools," 

School  Review,  20:246-53,  April,  1912. 
Stetson,  Paul  C.    "A  survey  of  supervised   studv,"  The   American    School   Board 

Journal.  54:19-20.  85-86,  June.  1917. 
Wiener,  William.    '"Home-study  reform,"  School  Review,  20:526-31,  October.  1912. 
Wiener,  William.  "The  social  value  of  school  study  versus  home  study,"  Chapter 

XI,   The   Modern    High   School,    edited   by    Chas.    H.    Johnston.    New   York: 

Charles  Scribner's  Sons,  1916.  p.  295-311. 
Willett,   G.  W.    "Supervised   study   in   high    school,"    School    Review.    26:259-72. 

April.  1918. 
Young,   Eula,    and   Simpson,    M.   R.     '"A   technique   for   the    lengthened   period," 

School  Review,  30:199-204,  March,  1922. 


[48] 


BULLETIN  NO.  27 


BUREAU  OF  EDUCATIONAL  RESEARCH 
COLLEGE  OF  EDUCATION 


EFFECT  OF  PRACTICE  ON 
INTELLIGENCE  TESTS 


By 


H.  N.  Click 

Professor  of  Educational  Psychology, 

Massachusetts  Agricultural  College 

Amherst,  Massachusetts 


(HE  UBHAHT  t!^  m 

JUL  15  iS2!) 

MNIVEIt^lTY  OF  a 


PRICE  30  CENTS 


PUBLISHED  BY  THE  UNIVERSITY  OF  ILLINOIS,  URBANA 

1925 


IX  ^ 


TABLE  OF  CONTEXTS 

PAGE 

Preface 4 

Chapter  I.     Introduction 5 

Chapter  II.     Experimental  Procedure 8 

Chapter  III.     Effect  of  Practice 13 

Chapter  IV.     Practical  Significance  of  Results 22 


PREFACE 

It  is  frequently  asserted  that  those  engaged  in  construct- 
ing and  using  educational  tests  have  not  examined  the 
assumptions  upon  which  these  instruments  are  based.  In 
fact,  some  critics  have  maintained  that  research  workers  in 
Education  were  not  aware  of  the  assumptions  implied  in  the 
instruments  and  procedures  which  they  are  accustomed  to 
employ.  In  his  study  of  '"Effect  of  Practice  on  Intelligence 
Tests,"  Doctor  Glick  has  rendered  a  valuable  service  by 
subjecting  assumptions  to  experimental  investigation. 
Although  critical  readers  may  point  out  certain  limitations 
of  the  data,  the  study  is  convincing.  It  is  obvious  that  our 
use  of  intelligence  tests  has  implied  an  assumption  which  is 
false,  and  that  in  consequence  many  of  the  scores  yielded  by 
these  tests  have  been  given  an  erroneous  meaning. 

The  publication  of  this  account  of  Doctor  Click's  inves- 
tigation should  serve  to  call  attention  to  the  need  for  explicit 
recognition  and  study  of  the  assumptions  implied  in  educa- 
tional tests.  Until  this  has  been  done,  our  use  of  these  instru- 
ments is  likely  to  lead  to  erroneous  conclusions. 

Walter  S.  Monroe,  Director. 
April  28,  1925. 


EFFECT  OF  PRACTICE  ON 

INTELLIGENCE  TESTS' 

CHAPTER  I 

INTRODUCTION 

Intelligence  tests  do  not  represent  the  first  attempt  to  measure 
lative  ability.  Palmistry,  phrenology,  physiognomy,  graphology  and 
Tiany  physical  tests  were  attempts  at  the  same  thing.  Each  was 
greeted  with  great  enthusiasm  and  was  hailed  as  a  means  for  securing 
/aluable  knowledge  relative  to  native  ability,  until  its  real  worth  and 
/alidity  were  determined  by  experimental  methods.  When  the 
assumptions  of  these  so-called  sciences  were  experimentally  analyzed, 
hey  were  removed  from  the  realm  of  practical  science  and  relegated 
o  the  domain  of  the  quack.  Group  intelligence  tests  have  recently 
attained  great  popularity,  but  we  are  just  beginning  to  examine  crit- 
cally  the  assumptions  upon  which  they  are  based. 

Assumptions  underlying  intelligence  tests.  Because  of  the  fact 
hat  intelligence  tests  measure  native  capacity  only  in  terms  of  be- 
havior, it  follows  that  such  measurement  must  be  indirect.  All  indi- 
rect measurements  involve  assumptions  that  need  to  be  examined 
larefuUy.  Among  the  assumptions  implied  in  our  present  procedures 
or  the  measurement  of  intelligence  are  the  following: 

I.  It  is  assumed  that  all  persons  tested  have  had  practically 
identical  environment  and  equal  opportunity  to  acquire  the  abil- 
ities for  which  a  test  calls. 

II.  It  Is  assumed  that  the  physical,  mental,  and  emotional 
status  of  the  different  subjects  is  practically  uniform  and 
constant. 

III.  It  is  assumed  that  initiative,  determination,  persever- 
ance, and  other  similar  qualities  which  are  usually  considered 
essential  to  success,  but  which  It  Is  not  claimed  our  tests  meas- 


^This  report  has  been  prepared  with  '"liberal  editmg"  from  a  manuscript  sub- 
nitted  by  Dr.  H.  N.  Ghck  in  partial  fulftUment  of  the  requirements  for  the  degree 
»f  doctor  of  philosophy  in  Education  in  the  Graduate  School  of  the  University  of 
llinois,  1924.  A  number  of  tables  and  discussions  of  minor  phases  of  the  study 
lave  been  omitted.  A  copy  of  the  original  report  is  on  file  in  the  University  of 
llinois  Library.  W.-^lter  S.  Monroe,  Director,  Bureau  of  Education  Research, 
Jniversity  of  Illinois. 

[S] 


lire,  either  approximate  a  perfect  correlation  with  the  traits 
measured,  or  do  not  affect  the  performances  which  the  tests 
require. 

IV.  It  is  assumed  that  the  functioning  of  the  abiUties  for 
which  a  test  calls  can  be  secured  at  any  time  and  that  they  are 
not  influenced  by  the  functioning  of  other  abilities. 

V.  It  is  assumed  that  general  testing  conditions  can  be 
controlled. 

\'I.   It   is    assumed   that   an    intelligence    test   score   is    not 

materially  increased  by  practice  or  coaching. 

Purpose  of  this  investigation.  The  purpose  of  this  study  is  to 
investigate  the  validity  of  the  last  of  the  assumptions  listed;  that  is, 
an  intelligence  test  score  is  not  materially  increased  by  practice  or 
coaching. 

General  procedure  employed.  A  procedure  was  devised  for 
securing  a  measure  of  the  effect  of  practice  upon  (1)  the  accuracy- 
of  the  pupil's  performance,  and  (2)  the  rate  of  his  performance.  Two 
types  of  practice  were  used:  (1)  repetition  of  exercises  similar  to, 
but  not  identical  with,  those  of  the  test  used  (practice  without  coach- 
ing), and  (2)  deliberate  coaching  for  the  tests  (practice  with 
coaching). 

Varying  effect  of  practice.  Investigations  of  the  effect  of  prac- 
tice show  that  the  amount  of  improvement  varies  greatly.  For  ex- 
ample, in  the  case  of  pitch  discrimination,  practice  produces  compara- 
tively little  improvement.  On  the  other  hand,  improvement  of  more 
than  1000  percent  has  been  shown  in  the  case  of  mirror  drawing.  It 
appears  therefore  that  we  have  no  general  basis  for  predicting  the 
amount  of  practice  effect  in  a  particular  case,  and  that  in  order  to 
ascertain  such  an  amount  it  is  necessary  to  institute  a  special  inquiry. 

Practice  with  identical  material  versus  practice  with  similar 
material.  We  have  practice  with  identical  material  in  learning  to 
operate  a  typewriter  or  a  telegraph  instrument  or  in  learning  to  play 
a  musical  instrument.  In  such  learning  the  object  is  to  acquire  skill 
in  the  performance  of  certain  specified  exercises. 

Practice  with  similar  material  occurs  in  such  subjects  as  arith- 
metic, algebra,  and  foreign  languages.    As  the  result  of  practice,  a 


'In  this  report  the  term  "accuracy"  has  a  somewhat  restricted  meaning.  The 
"accuracy"  of  the  pupil's  performance  is  measured  by  the  number  of  exercises  which 
he  does  correctly. 

[6] 


student  is  expected  to  acquire  skill  in  doing  exercises  similar  to,  but 
not  identical  with,  those  done  during  the  period  of  practice. 

Since  it  is  the  purpose  of  this  study  to  ascertain  the  effect  of 
practice  resulting  from  the  taking  of  intelligence  tests,  similar  material 
was  used.  The  use  of  identical  material  for  practice  would  have  been 
unfair  to  our  present  intelligence  tests,  because  it  is  assumed  that  the 
subjects  tested  have  no  previous  knowledge  of  the  particular  exer- 
cises which  they  are  asked  to  do.  In  fact,  in  most  cases  it  is  assumed 
that  they  have  no  definite  knowledge  of  the  particular  kinds  of  exer- 
cises of  which  the  intelligence  test  is  composed. 

Initial  assumptions.  The  writer  accepts  as  valid  two  conclusions 
of  biology  and  psychology:  (1)  that  general  intelligence  or  native 
ability  exists,  and  (2)  that  general  intelligence  varies  with  individ- 
uals. He  also  accepts,  with  certain  reservations,  the  assumption  that 
intelligence  tests  measure  native  ability. 


[7] 


CHAPTER  II 
EXPERIMENTAL  PROCEDURE 

Subjects  used.  The  subjects  used  in  this  investigation  were  as 
follows:  forty-five  students  in  the  seventh  and  eighth  grades  of  the 
Thornburn  School,  Urbana,  Illinois;  eighty-five  high-school  students, 
Urbana,  Illinois;  and  thirty-five  college  students  of  the  Massachu- 
setts Agricultural  College,  Amherst,  Massachusetts.'  Twenty-seven 
of  these  subjects  did  not  complete  all  of  the  tests  and  their  scores  are 
not  included  in  this  report. 

Tests  used  to  measure  intelligence.   Forms  5.  6,  7,  8,  and  9  of 

the  Army  Alpha  Intelligence  Examination  were  used  to  measure  the 
intelligence  of  the  subjects. 

Practice  materials.  The  writer  prepared  exercises  for  practice 
which  were  similar  to,  but  not  identical  with,  those  of  the  sub-tests 
of  the  Army  Alpha  Intelligence  Examination.  It  was  intended  to 
have  the  practice  exercises  equivalent  in  difficulty  to  the  correspond- 
ing Alpha  tests  but  there  is  no  experimental  proof  that  these  inten- 
tions were  realized.  Twenty  practice  forms  were  prepared  but  only 
fifteen  were  administered  because,  by  the  time  this  number  had  been 
used,  it  appeared  that  the  practice  had  been  carried  sufficiently  far 
for  the  purpose  of  this  investigation. 

In  constructing  the  practice  forms  an  efi^ort  was  made  to  exclude 
all  exercises  that  appeared  in  any  of  the  Alpha  forms.  In  a  few  in- 
stances the  same  exercises  were  used  in  two  or  more  of  the  practice 
forms.  The  number  of  items  in  each  sub-test  of  the  practice  forms 
was  the  same  as  in  the  corresponding  sub-test  of  the  Alpha  forms, 
with  the  exception  of  Sub-test  3,  in  which  fourteen  exercises  were 
used  instead  of  sixteen.  This  change  was  made  because  no  more  than 
fourteen  exercises  could  be  conveniently  mimeographed  on  one  page. 

The  administration  of  the  experiment.  The  writer  administered 
all  of  the  Alpha  forms,  as  well  as  the  practice  forms.  The  collection 
of  data  extended  from  October  9,  1922,  to  May  11,  1923.   The  sub- 

*The  writer  acknowledges  his  indebtedness  to  Superintendent  William  Harris, 
Urbana  Public  Schools,  Principal  M.  L.  Flaningam,  Urbana  High  School,  and  Prin- 
cipal R.  A.  Garrett,  Thornburn  School,  for  their  assistance  and  cooperation.  The 
students  of  the  Massachusetts  Agricultural  College  were  members  of  the  writer's 
class. 

[8] 


jects  were  handled  In  groups  ranging  in  size  from  twelve  to  twenty- 
iive.  In  the  following  tables  some  of  the  groups  include  more  than 
twenty-five  subjects.  In  such  cases  the  subjects  were  divided  into 
two  sections  for  the  administration  of  the  tests  and  practice  exercises, 
and  an  effort  was  made  to  keep  all  testing  conditions  constant,  except 
the  time  of  day  which  in  no  case  varied  more  than  two  hours. 

The  general  plan  of  the  experiment  was  to  begin  by  administer- 
ing one  of  the  Alpha  forms.  This  was  followed  on  successive  days 
by  the  administration  of  the  practice  forms  with  the  other  Alpha 
forms  being  given  at  more  or  less  regular  intervals.  It  was  decided 
more  or  less  arbitrarily  that  the  interval  between  the  administration 
of  the  several  forms  should  be  one  day,  with  the  exception  of  Satur- 
day, Sunday,  and  holidays.  The  work  was  interrupted  by  only  two 
holidays  and  these  interruptions  affected  only  two  groups.  The  order 
of  the  Alpha  forms  was  varied  to  correct  for  any  differences  in 
difficulty. 

Before  the  administration  of  the  first  Alpha  form,  the  subjects 
were  given  but  little  exact  information  concerning  the  nature  and 
purpose  of  the  work.  It  was  feared  that  some  might  not  make  a  dili- 
gent effort  on  the  first  trial  if  they  knew  that  the  purpose  of  the  work 
rwas  to  determine  the  amount  of  practice  effect.  After  the  admlnis- 
jtration  of  the  first  Alpha  form,  the  purpose  of  the  investigation  was 
tcarefully  explained  and  all  students  were  urged  to  improve  their 
scores  as  much  as  possible. 

The  instructions  for  each  Alpha  sub-test  were  given  in  full  on 
the  first  trial;  but,  except  for  the  first  sub-test,  were  omitted  on  sub- 
sequent trials.  \'ery  brief  instructions  were  given  for  the  first  prac- 
tice forms.  The  omission  of  instructions  doubtless  put  the  subjects 
to  some  disadvantage  but  the  effect  will  be  to  increase  the  validity 
of  the  findings.  In  the  practice  "without  coaching,''  the  subjects 
were  given  no  explanation  of  the  method  of  scoring  or  of  the  general 
principles  involved  in  the  tests.  In  the  ""practice  with  coaching,"  the 
principles  of  the  test  were  explained  and  shortcuts  for  doing  exercises 
were  pointed  out.  All  questions  raised  by  the  students  were  answered. 

Attitude  of  subjects.  The  attitude  of  the  subjects  toward  the 
tests  varied.  Some  were  very  cautious  and  did  carefully  all  that  they 
attempted.  Others  were  inclined  to  sacrifice  accuracy  for  rate  of 
work  and  evidently  resorted  to  guessing  at  times,  especially  when  a 
guess  would  stand  a  chance  of  being  correct. 


[9] 


It  was  anticipated  that  subjects  would  grow  exceedingly  weary 
of  the  work  before  the  end  of  the  four  weeks  of  daily  testing,  and  in 
order  to  offset  this  tendency  a  variety  of  incentives  was  introduced. 
The  subjects  were  told  of  their  scores  on  the  Alpha  forms  and  were 
encouraged  to  attempt  to  increase  their  scores  at  the  next  trial.  Treats 
in  the  form  of  candy  were  frequently  distributed,  both  in  the  Thorn- 
burn  School  and  in  the  high  school.  In  addition,  the  subjects  in  the 
Thornburn  School  were  promised  fifty  cents  if  they  continued  the 
work  to  the  end  of  the  fourth  week.  No  tangible  incentive  was  offered 
to  the  college  students,  but  all  were  members  of  the  writer's  classes 
in  education  and  appeared  to  be  interested  in  improving  their  scores. 
Under  these  conditions  an  expression  of  weariness  of  the  task  was 
very  unusual.  In  fact  a  number  of  the  subjects  expressed  regret 
when  the  work  was  completed. 

Method  of  measuring  rate  of  performance.  One  of  the  funda- 
mental requirements  of  test  construction  is  that  "the  test  should 
provide  adequate  opportunity  for  all  pupils  to  demonstrate  their 
abilities  in  the  field  defined  by  its  function."-  It  follows  that  the  time 
limit  for  a  rate  test  should  be  such  that  very  few,  if  any,  of  the  sub- 
jects will  do  all  of  the  exercises.  Seven  of  the  eight  sub-tests  of  the 
Army  Alpha  Intelligence  Examination  are  rate  tests,  and  after  prac- 
tice, only  one  subject  failed  to  finish  some  of  the  sub-tests  in  less 
than  the  time  allowed,  two  subjects  finished  the  sub-tests  in  less  than 
half  the  time  allowed,  and  a  number  finished  in  slightly  more  than 
half  time.  It  therefore  was  necessary  to  devise  some  means  for 
securing  a  record  of  the  time  actually  used  by  a  subject  when  he 
completed  the  sub-test  in  less  than  the  standard  time  allowed.  To 
accomplish  this,  a  large  clock  was  always  started  at  zero  time  for 
each  sub-test,  and  the  subjects  were  instructed  that,  if  they  should 
finish  any  test  before  time  was  called,  they  should  read  the  clock  to 
the  nearest  second  and  record  the  time  at  the  bottom  of  the  test. 

This  method  of  having  each  subject  record  his  ow^n  time  may  | 
be  questioned,  because  it  involves  opportunity  for  dishonesty.  In 
order  to  reduce  the  amount  of  cheating  to  a  minimum,  the  records 
of  the  subjects  were  checked  by  the  examiner,  who,  when  he  saw  a 
subject  look  at  the  clock  and  record  the  time,  would  also  record  the 
time  after  the  subject's  name.    Although  a  record  for  each  subject 


^Monroe,  Walter  S.    The  Theory  of  Educational  Measurements.    New  York: 
Houghton  Mifflin  Company,  1923.    p.  65. 

[10] 


was  not  obtained  each  day,  sufficient  samp^Ies  were  secured  to  postu- 
late with  considerable  certainty  the  accuracy  of  the  records  made  by 
the  subjects.  Only  three  instances  were  found  where  the  record  of 
the  examiner  did  not  talh'  within  two  seconds  that  of  the  subject. 

Statistical  treatment  of  data.  The  score  yielded  by  the  regular 
method  of  scoring  is  called  the  ''accuracy  score."  The  total  time  con- 
sumed in  completing  the  several  Alpha  sub-tests  is  called  the  "'rate 
score."  A  subject's  rate  score  and  accuracy  score  is  combined  into 
a  single  measure,  the  ''corrected  score. "^ 

The  forms  of  the  Army  Alpha  Intelligence  Examination  which 
were  used  are  known  to  yield  scores  that  are  somewhat  lacking  in 
equivalence.  However,  investigation  revealed  that  this  lack  of  equiv- 
alence resulted  in  errors  which  could  be  safely  neglected  in  the  com- 
parisons made  in  this  study. 

The  fact,  that  on  the  first  trial  the  subjects  in  general  did  not 
attempt  all  of  the  exercises  of  a  sub-test  in  the  time  allowed  and 
that  after  practice  they  generally  completed  a  test  in  less  than  the 
regular  time  allowance,  made  it  difficult  to  compute  the  percent  of 
increase  in  the  rate  score.  For  example,  Subject  Xo.  7,  Group  I, 
attempted  fifteen  of  the  twenty  problems  of  the  second  Alpha  sub- 
test and  did  nine  correctly.  On  the  last  trial  she  completed  all  of  the 
twenty  problems  in  three  minutes  and  eight  seconds  and  did  all  of 
them  correctly.  Obviously  these  two  records  are  not  directly  com- 
parable. It  is  necessary  that  both  be  expressed  in  terms  of  either 
the  number  of  examples  attempted  or  the  time  consumed.  Two  pro- 
cedures for  securing  an  initial  rate  score  were  considered:  first,  to 
compute  the  probable  time  that  would  have  been  required  to  com- 
plete the  sub-test  on  the  first  trial;  second,  to  use  the  standard  time 
allowance  as  the  initial  rate  score. 

The  first  procedure  is  open  to  the  objection  that  most  of  the 
sub-tests  are  scaled.  For  this  reason  it  is  likely  that  the  pupil's  actual 
rate  of  work  throughout  the  test  tends  to  decrease  as  he  advances  to 
the  more  difficult  exercises.  It  would  therefore  have  been  very  diffi- 
cult to  estimate  at  all  accurately  the  probable  time  required  for  a 


'The  "corrected  score"  was  derived  by  weighting  the  accuracy  score  in  propor- 
tion to  the  time  not  consumed.  For  example,  if  a  score  of  10  was  made  in  two 
minutes  when  the  standard  time  allowed  was  four  minutes,  the  '"corrected  score" 
would  be  20.  This  method  is  based  upon  the  assumption  that,  if  a  sufficient  number 
of  exercises  of  the  same  difficulty  had  been  supplied,  the  subject  would  have  main- 
tained the  same  rate  of  performance  for  the  total  time  that  he  did  for  the  actual 
time  consumed. 

[H] 


subject  to  complete  a  sub-test  on  the  first  trial.  Disregarding  the 
scaled  structure  of  the  sub-test  would  result  in  introducing  a  positive 
error  in  the  amount  of  practice  effect. 

The  second  method  implies  the  assumption  that  the  subject  did 
all  of  the  exercises  of  a  sub-test  on  the  first  trial.  This  is  not  true. 
In  fact  several  of  the  subjects  failed  to  complete  as  many  as  half 
of  the  exercises  on  the  first  trial.  However,  the  second  method  intro- 
duces a  negative  error  in  the  amount  of  practice  effect.  As  we  shall 
show  later,  the  effect  of  the  presence  of  such  an  error  is  to  increase 
the  validity  of  the  conclusions  reached.  For  this  reason,  this  method 
was  used  in  preference  to  the  one  described  in  the  preceding 
paragraph. 


ri2] 


CHAPTER  III 
EFFECT  OF  PRACTICE 

Distribution  of  testing  and  practice  without  coaching.    The 

distribution  of  testing  and  practice  without  coaching  is  shown  in 
Table  I.  It  should  be  read  as  follows:  Group  I  consisted  of  high- 
school  students:  five  freshmen,  five  sophomores,  and  two  juniors. 
(Two  subjects  failed  to  complete  the  experiment  and  their  records 
are  not  included.)  yXt  the  beginning  of  the  experiment,  they  were 
given  Form  5  of  the  Army  Alpha  Intelligence  Examination.  Follow- 
ing this,  eight  days  were  devoted  to  practice  which  consisted  of 
administering  tests  similar  to,  but  not  identical  with,  any  of  the 
forms  of  the  Army  Alpha  Intelligence  Examination.  Then  Form  6 
was  administered,  followed  by  three  days  of  practice  and  so  on.  For 
this  group  the  experiment  really  closed  with  the  administration  of 
Form  9.  The  data  for  the  other  groups  are  to  be  read  in  the  same 
way.  It  will  be  noted  that  there  was  some  variation  in  the  length 
of  the  periods  of  practice  for  the  different  groups. 

Gains  due  to  practice.  Table  II  presents  a  summary  statement 
of  the  average  gains^  made  by  the  five  groups  that  received  practice 
without  coaching.  In  computing  the  number  of  periods  of  practice 
given  in  the  second  column  of  the  table,  the  "trials''  between  the  first 
and  last  are  included.  It  should  also  be  noted  that  the  scores  made 
on  Form  8  were  not  used  in  the  case  of  Groups  I,  II,  and  I\'.  The 
"accuracy  score''  has  been  defined  as  the  score  obtained  by  the  reg- 
ular method.  In  other  words,  it  is  the  number  of  exercises  done 
correctly.  Table  II  is  to  be  read  as  follows:  At  the  end  of  the  experi- 
ment, the  average  accuracy  score  of  Group  I  was  35  points  greater 
than  at  the  beginning,  (absolute  gain).  This  represents  an  increase 
of  30.1  percent  over  the  average  initial  score,  (relative  gain).  The 
"absolute  gain"  in  "rate  score"  is  5:25  (read  5  minutes  and  25  sec- 
onds) and  the  relative  gain  is  27.8  percent.  For  the  "corrected  score" 
the  two  measures  of  gain  are  111.6  percent  and  88.4  percent. 

In  interpreting  the  facts  given  in  this  table,  it  should  be  noted 
that  on  the  final  testing  (fourth  trial)  many  of  the  subjects  finished 


^The  median  gains  were  also  computed,   but  since  they  did  not  differ  materi- 
ally from  the  average,  they  are  omitted  from  the  report. 

[13] 


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[14] 


TABLE  II.   AVER.\GE,  ABSOLUTE  AND  RELATIVE  GAIN  IX  ACCURACY. 
RATE  AND  CORRECTED  SCORES  (PRACTICE  WITHOUT  COACHING) 


Number 

of 
Days  of 

Accuracy  Score 

Rate 

Score 

Corrected  Score 

Group 

Absolute 

Relative 

Absolute 

Relative 

Absolute 

Relative 

Practice 

Gain 

Gain* 

Gain 

Gain 

Gain 

Gain 

I 

19 

35.0 

30.1 

5:25 

27.8 

111.6 

88.4 

II 

19 

36.9 

44.1 

4:21 

22.3 

84.0 

90.4 

III 

19 

36.7 

33.5 

5:20 

27,3 

104.8 

87.6 

IV 

20 

36.5 

42.3 

3:41 

19.1 

74.6 

79.4 

V 

14 

28.7 

19.3 

5:06 

26.8 

99.0 

57.9 

Total 

16.5 

33.7 

31.4 

4:38 

24.6 

83.8 

75.8 

*A11  relative  gains   are  expressed   in  terms  of  percent. 

some  of  the  sub-tests  in  less  than  the  regular  time  allowance  and  for 
this  reason  the  accuracy  score  does  not  furnish  a  true  measure  of  the 
effect  of  the  practice.  A  measure  of  the  decrease  in  the  time  required 
for  completing  the  Army  Alpha  Intelligence  Examination  is  given 
by  the  average  gain  in  rate  which  is  5:25  for  Group  I.  An  approx- 
imate interpretation  of  this  statement  is  that  on  the  average  the 
subjects  of  Group  I  completed  the  sub-tests  in  five  minutes  and 
twenty-five  seconds  less  than  the  regular  time  allowance.  Since  on 
the  first  trial,  few  of  the  subjects  completed  all  of  the  exercises  of  the 
sub-tests  within  the  time  allowed,  this  "gain  in  rate"  does  not  give 
us  a  true  measure  of  the  effect  of  practice  upon  the  rate  of  work 
on  the  test.  The  "corrected  score"  gives  a  more  truthful  statement 
of  the  effect  of  practice,  and  as  might  be  expected,  the  gains  for  this 
score  are  larger  than  for  either  the  "accuracy  score"  or  the  "rate 
score."  though  still  not  large  enough. 

The  "corrected  score"  does  not  tell  the  whole  truth,  because  it 
does  not  take  into  account  the  fact  that  on  the  first  trial  most  of 
the  subjects  did  not  complete  the  sub-tests  within  the  time  allowed. 
The  average  gain  in  rate  for  the  five  groups  combined  was  estimated 
to  be  9:58.  instead  of  4:37,  as  shown  in  Table  II.  The  gain  for  the 
corresponding  corrected  score  is  162.9  points  or  a  relative  gain  of 
131.7  percent,  instead  of  93.8  points  and  75.8  percent.  Obviously  the 
average  gains  shown  in  Table  II  are  considerably  smaller  than  the 
real  gains.  This  limitation  of  the  data,  however,  is  not  a  serious  one 
because  the  gains  given  are  relatively  large. 

It  is  obvious  from  the  facts  given  in  Table  II  that  practice  with- 
out coachine  results  in  verv  material   increases  in  the  scores  made 


[15] 


on  an  intelligence  test  of  the  type  represented  by  the  Army  Alpha 
Intelligence  Examination.  The  average  corrected  scores  for  the  three 
groups  that  had  nineteen  periods  of  practice  show  gains  of  from  84 
to  111  points.  With  the  exception  of  Group  \',  which  had  a  relatively 
large  average  initial  score,  the  gains  are  in  excess  of  75  percent  of 
the  initial  score.  Since  the  method  of  computing  the  effect  of  prac- 
tice minimized  its  magnitude,  it  appears  probable  that,  if  a  true 
measure  of  the  effect  of  practice  had  been  secured,  considerably  more 
than  half  of  the  subjects  would  have  been  found  to  have  doubled 
their  initial  scores  as  the  result  of  approximately  seven  hours  of 
practice. 

Although  no  specific  attempt  was  made  to  investigate  the  ques- 
tion, some  data  were  secured  in  the  course  of  the  experiment  which 
indicated  that  the  limit  of  the  effect  of  practice  was  not  reached  by 
the  end  of  the  fourth  week.  Hence,  if  additional  practice  had  been 
given  the  subjects,  it  is  likely  that  some  additional  gains  would  have 
been  made. 

The  distribution  of  testing  and  practice  with  coaching.  It  was 
the  original  intention  to  confine  this  experiment  to  the  determination 
of  the  effects  of  practice  without  coaching  but,  in  the  course  of  the 
work,  the  subjects  asked  so  many  questions  concerning  the  nature 
of  the  exercises  of  the  sub-tests  and  the  procedure  in  doing  them 
that  it  was  decided  to  give  two  groups  practice  with  coaching.  The 
first  of  these,  which  is  called  Group  \T,  consisted  of  thirty-three 
subjects  in  the  Urbana  High  School.  Twenty-six  completed  the 
work:  one  senior,  eight  juniors,  seven  sophomores,  and  ten  freshmen. 
Group  \  II  consisted  of  twent\'-four  subjects  in  the  Thornburn 
School.  Twenty-two  completed  the  work:  eleven  seventh-grade  and 
eleven  eighth-grade  pupils. 

The  same  experimental  procedure  was  followed  for  both  groups. 
Form  7  of  the  Army  Alpha  Intelligence  Examination  was  given  at 
the  beginning  of  the  experiment.  On  the  second  day,  a  half  hour  was 
devoted  to  an  explanation  of  the  method  of  scoring  and  a  discussion 
of  the  principles  and  "'shortcuts"  relating  to  Sub-tests  Xo.  1  (Instruc- 
tions Test)  and  Xo.  5  (True-False).  All  questions  that  the  subjects 
cared  to  ask  were  answered.  On  the  third  day.  Form  5  was  admin- 
istered. The  fourth  day  was  devoted  to  coaching  on  Sub-tests  Xo.  2 
(Problems)  and  Xo.  6  (Xumber  Composition).  The  fifth  day  was 
devoted  to  practice  with  a  review  of  the  instructions  previously  given. 

[16] 


TABLE  III.   EFFECT  OF  "PRACTICE  WITHOUT  COACHING"  COMPARED 

WITH  EFFECT  OF  "PRACTICE  WITH  COACHING"  (PERIOD 

OF  PRACTICE  TWO  WEEKS) 


Groups 

Number 

of 
Subjects 

Accuracy  Score 

Rate  Score 

Corrected  Score 

Absolute 
Gain 

Relative 
Gain* 

Absolute 
Gain 

Relative 
Gain 

Absolute 
Gain 

Relative 
Gain 

^.  lancill 

Without 
Coaching 

27 

25.5 

21.3 

3:58 

20.2 

72.7 

59.2 

VI 

With 
Coaching 

26 

36.6 

32.2 

2:44 

14.2 

71.7 

58.4 

IV 

Without 
"     Coaching 

22 

22.9 

25.5 

3:3S 

18.4 

53.2 

56.1 

VII 

With 
Coaching 

17 

33.6 

38.2 

2:10 

10.8 

53.8 

60.3 

I,  II,  IV 

Without 
Coaching 

49 

24.6 

23.1 

3:50 

9.9 

65.17 

59.7 

VI,  VII 

With 

Coaching 

43 

35.4 

34.6 

2:30 

12.8 

64.6 

59.2 

*AII    relative  gains  are  expressed   in  terms   of  percent. 

Form  9  was  administered  on  the  sixth  day  and  Form  6  on  the  eighth 
day.  The  seventh  and  ninth  days  were  devoted  to  coaching  and 
practice  on  some  of  the  most  difficult  exercises.  Form  8  was  given 
on  the  tenth  day.  The  periods  devoted  to  practice  varied  from 
twenty-five  to  thirty  minutes. 

In  order  to  provide  data  for  comparison  with  the  gains  made 
by  these  two  groups,  the  gains  made  by  three  other  groups  were 
calculated  at  the  end  of  the  second  week  of  the  experiment.  In 
Table  III,  the  gains  for  Groups  I  and  II  have  been  combined  so 
that  comparison  may  be  made  with  the  gains  for  Group  VI.  The 
average  initial  score  of  Groups  I  and  II  combined  was  119.5,  and 
that  of  Group  VI,  122.7.  Even  this  difference  tends  to  become  insig- 
nificant when  the  differences  in  the  difficulty  of  the  forms  of  the 
Army  Alpha  Intelligence  Examination  upon  which  these  gains  are 
based  are  considered.    Hence,  we   may  consider  Groups   I   and   II 


[17] 


TABLE  I\-.   AVER.\GE  GAINS  ON  THE  SEPAR-\TE  SUB-TESTS 
(ALL  GROUPS  CO-MBINED) 


Accuracy  Score 

Rate 

Score 

Corrected   Score 

Sub-test 

Absolute       Relative 

Absolute 

Relative 

Absolute 

Relative 

Gain       ]      Gain* 

Gain 

Gain 

Gain 

Gain 

1 

3.61 

49.8 

2 

3.57 

33.1 

1:23.4 

27.9 

9.85 

85.4 

3 

2.32 

23.4 

7.4 

8.3 

4.08 

40.3 

4 

2.06 

15.9 

13.9 

15.4 

7.23 

47.5 

5 

3.93 

30.8 

36.5 

31.0 

14.03 

86.2 

6 

5.67 

55.4 

31.6 

17.6 

10.25 

99.1 

7 

8.55 

34.6 

29.7 

16.6 

11.87 

70.4 

8 

2.66 

12.7 

57.8 

27.0 

17.10 

62.4 

*.A11   relative   gains   are  expressed   in  terms  of  percent. 


comparable    with     Group     \  I     and     Group     I\"    comparable     with 
Group  VII. 

An  inspection  of  Table  III  reveals  the  fact  that  in  every  instance 
the  groups  which  received  ''practice  with  coaching"  made  greater 
gains  in  accuracy  but  less  in  rate  than  those  which  received  "'practice 
without  coaching."'  This  superiority  in  accuracy  exhibited  by  the 
groups  which  received  "practice  with  coaching"  is  doubtless  due  to 
the  fact  that  these  subjects  had  a  better  understanding  of  the  types 
of  exercises  which  made  up  the  several  sub-tests.  Their  inferiority 
in  rate  was  probabh-  due  to  conscious  attempts  to  apply  what  they 
had  learned  through  coaching.  The  average  gains  as  measured  by 
"corrected  scores"  are  practically  the  same  for  the  two  types  of  prac- 
tice. This  fact  suggests  the  statement  that  "practice  without  coach- 
ing" has  approximately  the  same  effect  upon  the  scores  yielded  by 
intelligence  tests  as  "practice  with  coaching,"  but  an  analytical  study 
of  the  data  indicates  that  the  latter  type  of  training  is  likely  to  pro- 
duce a  distinctly  greater  increase  in  the  scores  yielded  by  our  present 
intelligence  tests. 

Effect  of  practice  upon  the  separate  sub-tests.  Since  a  subject's 
score  on  the  Army  Alpha  Intelligence  Examination  is  the  sum  of  the 
scores  on  eight  sub-tests,  the  question  concerning  the  distribution  * 
of  the  effect  of  practice  naturally  arises.  Table  IV  gives  the  total 
average  gains  separately  for  these  sub-tests.'  As  none  of  the  three 
scores  furnishes  a  very  accurate  measure  of  the  improvement  in  a 


Tn  computing  the  averages  given  in  Table  IV,  the  data  for  all  seven  groups 
were  included. 

[18] 


subject's  performance,  it  is  not  possible  to  make  comparison  between 
the  results  for  the  different  sub-tests.  It  is,  however,  obvious  that 
practice  affected  a  subject's  score  on  each  of  the  sub-tests. 

Relation  of  effect  of  practice  to  amount  of  schooling.  It  is 
apparent  from  Table  II  that  very  large  gains  were  made  by  all 
groups  of  subjects.  In  order  to  determine  more  accurately  the  rela- 
tion of  the  effect  of  practice  to  the  amount  of  schooling,  the  subjects 
were  classified  according  to  school  grade.  The  crudeness  of  the  meas- 
ures of  the  effect  of  practice  tends  to  destroy  the  significance  of  small 
differences  between  gains  made  by  different  groups,  but  Table  II, 
as  well  as  the  similar  table''  obtained  by  classifying  the  subjects 
according  to  school  grade,  suggests  that  for  subjects  above  the  sixth 
grade  the  effect  of  practice  is  not  materially  affected  by  the  amount 
of  schooling. 

Persistency  of  practice  effect.  In  order  to  secure  a  measure  of 
the  persistency  of  practice  effect,  Form  8  was  given  to  seven  subjects 
of  Group  I  seventy-three  days  after  the  close  of  the  experimental 
period,  and  to  eleven  subjects  of  Group  II  forty  days  after  the  close 
of  the  period  of  practice.  The  subjects  from  Group  I  showed  an 
average  loss  of  9.4  points  in  accuracy  and  2:13  in  time.  The  subjects 
from  Group  II  gained  a  fraction  of  a  point  in  accuracy  and  lost  1:44 
in  time.  Examination  of  the  records  of  these  groups  during  the 
period  of  practice  reveals  that  Group  I  made  a  decided  gain  on  the 
fourth  trial  of  the  Army  Alpha  Intelligence  Examination,  which  was 
given  at  the  end  of  the  experimental  period.  This  probably  accounts 
in  part  for  the  relatively  large  decrease  in  the  scores  made  on  Form  8, 
which  was  administered  seventy-three  days  afterwards. 

Five  college  students,  who  had  an  average  accuracy  score  of 
187  at  the  close  of  the  practice  in  May,  1923,  were  given  the  test  in 
the  following  December.  Their  average  score  was  approximately 
the  same.  It  appears  therefore  that  the  effect  of  practice  tends  to 
persist.  Hence,  a  subject  who  has  once  received  practice  probably 
will  always  make  relatively  high  scores  upon  an  intelligence  test 
of  similar  type.^ 


^This  table  is  omitted  from  this  published  report. 

^Forty-three  of  the  pupils,  who  were  in  the  seventh  and  eighth  grades  and  the 
high  school  at  the  time  of  this  experiment,  were  given  Form  5  of  the  Army  Alpha 
Intelligence  Examination  about  the  end  of  February,  1925.  This  test  was  not  ad- 
ministered by  Doctor  Click  and  some  of  the  other  testing  conditions  were  not 
identical  with  those  of  his  experiment.    Several  of  these  subjects  took  Form  5   at 

[19] 


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Effect  of  practice  "without  coaching"  upon  correlation  of  test 
scores  with  school  marks.  Table  V  presents  certain  coefficients  of 
correlation  between  intelligence  test  scores  and  the  average  of  the 
school  marks  received  by  the  subjects  at  the  end  of  the  semester, 
during  which  the  experiment  was  carried  on.  If  we  compare  the 
coefficients  of  correlation  for  the  scores  resulting  from  a  first  trial 
with  the  corresponding  coefficients  of  correlation  for  the  last  trial, 
we  find  that  with  the  exception  of  one  case  practice  served  to  increase 
the  degree  of  correlation.  Since  the  scores  for  the  last  trial  of  the 
intelligence  test  involve  a  variable  negative  error  (see  page  12),  the 
coefficients  of  correlation  with  average  semester  grades  are  somewhat 
smaller  than  they  would  be  if  "true  scores"  had  been  used.  Hence,  it 
appears  that,  as  subjects  become  familiar  with  an  intelligence  test, 
we  may  expect  the  scores  yielded  by  such  tests  to  correlate  more  and 
more  closely  with  school  achievements  as  measured  by  semester 
grades. 


the  beginning  of  Doctor  Click's  experiment.  The  scores  of  the  others  were  reduced 
to  the  basis  of  Form  5  before  calculating  the  increase  of  the  scores  secured  in  Feb- 
ruary, 1925,  over  those  made  in  the  autumn  of  1922.  The  results  show  that  the 
persistency  of  practice  effect  over  the  period  of  more  than  two  years  was  very 
slight.  In  other  words,  the  differences  between  the  scores  made  at  this  last  testing 
and  those  made  on  the  first  testing,  (the  one  at  the  beginning  of  the  experiment) 
were  only  slightly  greater  than  would  have  been  expected  from  the  fact  that  the 
pupils  concerned  were  more  than  two  years  older  at  the  time  when  the  last  test 
was  given. 

Note  by  Walter  S.  Monroe,  Director,  Bureau  of  Educational  Research,  Uni- 
versity of  Illinois. 

[21] 


CHAPTER  IV 
PRACTICAL  SIGNIFICANCE  OF  RESULTS 
Use  of  intelligence  tests  in  determining  fitness  for  college.  The 

data  presented  in  Table  II  demonstrated  that  practice  with  similar 
material  results  in  very  significant  increases  in  the  scores  made  on 
an  intelligence  test  of  the  type  used  in  this  experiment.  This  con- 
clusion suggests  a  question  which  may  be  stated  as  follows :  If  from 
seven  to  ten  hours  of  practice  causes  a  majority  of  subjects  to  double 
their  scores  on  intelligence  tests,  do  these  instruments  have  any  value 
for  determining  the  fitness  of  candidates  for  college  entrance?  The 
types  of  material  used  in  intelligence  tests  and  even  intelligence  tests 
themselves  are  now  the  common  property  of  all  who  desire  them. 
If  such  tests  are  used  regularly  by  an  institution  to  determine  the 
fitness  of  those  who  seek  entrance,  it  is  reasonable  to  e.xpect  that 
many  candidates  will  deliberately  prepare  for  the  tests.  It  is  evident, 
from  the  facts  presented  in  Chapter  III,  that  we  must  expect  material 
increase  in  scores  to  result  from  general  acquaintance  with  the  exer- 
cises used  in  intelligence  tests  and  a  much  greater  increase  when 
there  is  extended  practice  or  deliberate  coaching. 

The  fact  that  practice  results  in  increased  scores  does  not 
necessarily  invalidate  the  measures  yielded  by  general  intelligence 
tests  as  a  basis  for  college  entrance.  If  all  subjects  had  received  th 
same  amount  of  practice,  it  is  likely  that  the  scores  obtained  would 
approach  comparability  and  hence  possess  validity  as  measures  of 
general  intelligence.  This  condition  is  not  realized  in  most  groups  to 
which  an  intelligence  test  is  given.  Some  of  the  subjects  may  have 
had  no  experience  in  taking  an  intelligence  test  and  most  of  the  types 
of  exercises  included  in  the  test  may  be  strange  to  them.  Others 
may  have  taken  this  or  a  similar  test  one  or  more  times.  A  few  may 
have  received  extended  training  or  coaching. 

Data  gathered  in  this  study  indicate  that  approximately  70  per- 
cent of  the  maximum  increase  in  scores  due  to  practice  is  attained 
on  the  fifth  repetition.  This  suggests  that  a  partial  equalization  of 
practice  may  be  secured  by  repeating  the  intelligence  tests  from 
three  to  five  times,  using  different  forms  and  recording  only  the  scores 
made  on  the  final  trial.  This  statement  is  supported  by  the  fact  that 

[22] 


intelligence  scores   secured   after   practice   show   higher  correlations 
with  average  school  marks. 

Correction  of  norms  for  practice  effect.    Since  norms  for  intelli- 
gence   tests    are    usually   based    upon    initial    scores    of    unpracticed 

I  subjects,  it  is  obvious  that  such  norms  will  lead  to  an  erroneous 
interpretation  of  the  scores  made  by  subjects  who  have  received 
practice.  In  fact  norms  determined  for  first-trial  scores  are  not  suit- 
able for  interpreting  scores  made  on  a  second  trial  of  the  same  test. 
In  the  ordinary  use  of  general  intelligence  tests,  no  attempt  is  made 
to  ascertain  the  amount  of  practice  which  the  various  subjects  have 
received,  but  in  many  cases  it  is  likely  that  at  least  a  few  of  the  sub- 
jects have  taken  an  intelligence  test  on  some  previous  occasion.  If 
there  are  such  subjects  in  the  group  tested,  it  is  inappropriate  to  use 
our  present  norms  as  a  basis  for  interpreting  their  scores. 

The  problem  here  is  similar  to  that  noted  in  connection  with 
the  use  of  tests  for  determining  fitness  for  college.   Probably  the  best 

[solution  would  be  to  determine  norms  for  scores  made  after  a  certain 
amount  of  practice,  say  on  the  fifth  trial.  Then,  when  using  an  intel- 

i  ligence  test,  it  would  be  administered  five  times  and  only  the  scores 

■from  the  last  trial  counted. 


[23] 


BULLETIN  NO.  28 


BUREAU  OF  EDUCATIONAL  RESEARCH 
COLLEGE  OF  EDUCATION 

SOURCE  STUDIES  IN  AMERICAN 
COLONIAL  EDUCATION 

THE  PRIVATE  SCHOOL 

By 

Robert  Franxis  Seybolt 

Associate  Professor  of  the  History  of  Education 
University  of  Illinois 


PRICE  50  CENTS 


PUBLISHED  BY  THE  UNIVERSITY  OF  ILLINOIS,  URBANA 

192S 


UNIVERSITY  OF  ILLINOIS-URBANA 


3  0112  0700715 


